Hoping for my rainbow...🌈😔

I had a miscarriage on 29.4.16 and I'm still waiting for AF to show, which doesn't feel like any time soon. It's been four weeks since my miscarriage & I've had negative tests since the day of miscarriage. I have been feeling the same way I did when I was pregnant before ( a week before we found out) and I took a test after a 4 hour hold without drinking & it was negative :( could it be too early?? My doctor cleared us that we could TTC straight away. Just wondering when I should test again?? Please help girls. I'm sick of seeing negatives 😔💭🌈